This article includes a list of countries by their forecasted estimated "gross domestic product based on "purchasing power parity, abbreviated GDP (PPP).[2] Countries are sorted by GDP PPP forecast estimates from financial and statistical institutions in the limited period January-April 2017, which are calculated at market or government official "exchange rates. The data given on this page are based on the "international dollar, a standardized unit used by economists.

GDP comparisons using PPP are arguably more useful than those using nominal GDP (see "List of countries by GDP (nominal)) when assessing a nation's domestic market because PPP takes into account the relative cost of local goods, services and inflation rates of the country, rather than using international market exchange rates which may distort the real differences in per capita income.[3] It is however limited when measuring financial flows between countries.[4] PPP is often used to gauge global "poverty thresholds and is used by the "United Nations in constructing the "human development index.[3] These surveys such as the International Comparison Program include both tradable and non-tradable goods in an attempt to estimate a representative basket of all goods.[3]

^ abcThe European Union (EU) is an "economic and "political union of 28 "member states that are located "primarily in "Europe. The EU is included because it has many attributes of independent nations, being much more than a free-trade association such as ASEAN, NAFTA, or Mercosur.[9] As the EU is not a country, the U.S. is the second ranked country on these lists.

^a China's PPP is based on prices for 11 administrative regions, extrapolated to the full country, and an urban/rural breakdown. China's entry does not include the two "special administrative regions, namely "Hong Kong and "Macau. These are listed separately.

^"CIA (2014). "The World Factbook". Retrieved 15 March 2015. Although the EU is not a federation in the strict sense, it is far more than a free-trade association such as ASEAN, NAFTA, or Mercosur, and it has certain attributes associated with independent nations: its own flag, currency (for some members), and law-making abilities, as well as diplomatic representation and a common foreign and security policy in its dealings with external partners. Thus, inclusion of basic intelligence on the EU has been deemed appropriate as a new, separate entity in The World Factbook.